// Copyright 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_INPUT_SCROLLBAR_ANIMATION_CONTROLLER_LINEAR_FADE_H_
#define CC_INPUT_SCROLLBAR_ANIMATION_CONTROLLER_LINEAR_FADE_H_

#include <memory>

#include "base/macros.h"
#include "cc/base/cc_export.h"
#include "cc/input/scrollbar_animation_controller.h"

namespace cc {

class CC_EXPORT ScrollbarAnimationControllerLinearFade
    : public ScrollbarAnimationController {
public:
    static std::unique_ptr<ScrollbarAnimationControllerLinearFade> Create(
        int scroll_layer_id,
        ScrollbarAnimationControllerClient* client,
        base::TimeDelta delay_before_starting,
        base::TimeDelta resize_delay_before_starting,
        base::TimeDelta duration);

    ~ScrollbarAnimationControllerLinearFade() override;

    void DidScrollUpdate(bool on_resize) override;

protected:
    ScrollbarAnimationControllerLinearFade(
        int scroll_layer_id,
        ScrollbarAnimationControllerClient* client,
        base::TimeDelta delay_before_starting,
        base::TimeDelta resize_delay_before_starting,
        base::TimeDelta duration);

    void RunAnimationFrame(float progress) override;
    const base::TimeDelta& Duration() override;

private:
    float OpacityAtTime(base::TimeTicks now) const;
    void ApplyOpacityToScrollbars(float opacity);

    base::TimeDelta duration_;

    DISALLOW_COPY_AND_ASSIGN(ScrollbarAnimationControllerLinearFade);
};

} // namespace cc

#endif // CC_INPUT_SCROLLBAR_ANIMATION_CONTROLLER_LINEAR_FADE_H_
